• Title, Summary, Keyword: K Bank

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Study on Surge Response Characteristics and Surge Current Reduction for 154kV Shunt Capacitor Bank (154kV SC Bank의 써지 응답특성과 써지전류 저감에 관한 연구)

  • Hur, Yong-Ho;Choi, Myung-Kuk;Lee, Sang-Il;Jung, Jea-Kee
    • Proceedings of the KIEE Conference
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    • pp.329-334
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    • 2002
  • 우리나라 전력계통의 특성상 남부의 전원단과 수도권의 부하중심단과의 거리가 존재하여 안정적인 계통전압제어에 어려움이 존재한다. 이러한 계통전압제어의 어려움을 극복하기 위해 154kV 계통에 SC Bank를 설치 운용중에 있다. 운전 환경상 차단기의 투입과 차단이 잦은 154kV SC Bank에 리액터가 소손되는 등의 문제점이 발생하고 있어 154kV SC Bank의 써지응답특성을 규명하고 차단기의 투입차단시 발생하는 써지전류의 저감에 대한 연구의 필요성이 대두되고 있다. 본 연구에서는 154kV SC Bank를 대상으로하여 현장조사와 현장실증을 통해 써지전류를 측정하고, 모의를 통해 써지응답특성을 규명하였다. 그 결과, 차단기의 접점의 상태와 피뢰기의 동작여부에 의해 써지전류가 크게 영향을 받는다는 점을 확인하였다. 154kV SV Bank를 대상으로 한 현장시험과 서지응답특성의 분석결과를 기본으로 하여 피뢰기의 영향과 차단기의 투입차단 영향을 최소화하는 방안으로 피뢰기의 분리운전으로 전류재단현상을 막아 급준써지전류의 발생을 억제하고 저항투압방식의 차단기로 써지전류를 30%이하로 억제할 수 있음을 실증과 모의로 확인하였다.

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Biotransformation of Ginsenoside Rb1 to Prosapogenins, Gypenoside XVII, Ginsenoside Rd, Ginsenoside F2, and Compound K by Leuconostoc mesenteroides DC102

  • Quan, Lin-Hu;Piao, Jin-Ying;Min, Jin-Woo;Kim, Ho-Bin;Kim, Sang-Rae;Yang, Dong-Uk;Yang, Deok-Chun
    • Journal of Ginseng Research
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    • v.35 no.3
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    • pp.344-351
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    • 2011
  • Ginsenoside $Rb_1$ is the main component in ginsenosides. It is a protopanaxadiol-type ginsenoside that has a dammarane-type triterpenoid as an aglycone. In this study, ginsenoside $Rb_1$ was transformed into gypenoside XVII, ginsenoside Rd, ginsenoside $F_2$ and compound K by glycosidase from Leuconostoc mesenteroides DC102. The optimum time for the conversion was about 72 h at a constant pH of 6.0 to 8.0 and the optimum temperature was about $30^{\circ}C$. Under optimal conditions, ginsenoside $Rb_1$ was decomposed and converted into compound K by 72 h post-reaction (99%). The enzymatic reaction was analyzed by highperformance liquid chromatography, suggesting the transformation pathway: ginsenoside $Rb_1$ ${\rightarrow}$ gypenoside XVII and ginsenoside Rd${\rightarrow}$ginsenoside $F_2{\rightarrow}$compound K.

Bioconversion of Ginsenoside Rd into Compound K by Lactobacillus pentosus DC101 Isolated from Kimchi

  • Quan, Lin-Hu;Cheng, Le-Qin;Kim, Ho-Bin;Kim, Ju-Han;Son, Na-Ri;Kim, Se-Young;Jin, Hyun-O;Yang, Deok-Chun
    • Journal of Ginseng Research
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    • v.34 no.4
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    • pp.288-295
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    • 2010
  • Ginsenosides are the principal components responsible for the pharmacological and biological activities of ginseng. Ginsenoside Rd was transformed into compound K using cell-free extracts of food microorganisms, with Lactobacillus pentosus DC101 isolated from kimchi (traditional Korean fermented food) used for this conversion. The optimum time for the conversion was about 72 h at a constant pH of 7.0 and an optimum temperature of about $30^{\circ}C$. The transformation products were identified by thin-layer chromatography and high-performance liquid chromatography, and their structures were assigned using nuclear magnetic resonance analysis. Generally, ginsenoside Rd was converted into ginsenoside F2 by 36 h post-reaction. Consequently, over 97% of ginsenoside Rd was decomposed and converted into compound K by 72 h post-reaction. The bioconversion pathway to produce compound K is as follows: ginsenoside Rd$\rightarrow$ginsenoside F2$\rightarrow$compound K.

Research for Protection Relay of Static Condenser Bank (SC 전용 보호계전기 개발)

  • Jeong, J.K.;Yun, S.Y.;Kim, S.J.;Kim, K.G.
    • Proceedings of the KIEE Conference
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    • pp.48-50
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    • 2006
  • SC(Static Condenser) in KEPCO is used in voltage control and power factor compensation. Currently KEPCO uses SC to 154kv 50MVA and 23kv SMVA. It is not important in old days because a SC bank accident has no effect on power system. But we are interested in the SC bank for power quality in these days. The SC Bank has a reactor and a condenser using series connection. It is operated in critical point for resonance circuit normally. Therefore the SC bank has a small reliability against other Power instruments. If a 4th harmonic frequency as a resonance frequency is supplied in system, the condenser is damaged because of a resonance current. And a trip and a closing for CB(Circuit Breaker) in many times will have a big influence of SC bank destruction. General OCR(Over Current Relay) observing SC bank is not useful for this protection We think that protection relay must be have the SC bank characteristics. A solution for this problem is active Power, resonance frequency and impedance.

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Advanced Load Follow Operation Mode for Korean Standardized Nuclear Power Plants (한국 표준 원전의 부하추종을 위한 운전 기법)

  • Park, Jung-In;Oh, Soo-Youl;Song, In-Ho;Hah, Yung-Joon;Kuh, Jung-Eui;Lee, Un-Chul
    • Nuclear Engineering and Technology
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    • v.24 no.2
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    • pp.183-192
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    • 1992
  • An advanced load-follow operation mode, Mode K, is presented for the Korean Standardized Nuclear Power Plants. The Mode K utilizes a heavy worth bank dedicated to axial shape control independent of the existing regulating banks. In Mode K, the heavy bank provides a wide range of axial shape control and a monotonic relationship between its motion and the axial shape change, which makes it easy to automate axial shape control. The achievement of full automatic reactor power control both for the reactivity and power shape would reduce the burden due to load-follow operation on the operator. Also, it can accommodate the frequen-cy control, which requires the plant to respond to the unexpected demand. The Mode K design concepts were tested using simulation responses of Yonggwang Units 3&4, the reference plants for the Korean Standardized Nuclear Power Plants. The results illustrate that the Mode K is an adequate operation mode to provide practical load-follow capabilities for the Korean Standardized Nuclear Power Plants.

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Evaluation of 300kJ Capacitor Bank Module for High Current Pulse Shaping (대전류 펄스 성형을 위한 300kJ급 커패시터뱅크 모듈의 특성 평가)

  • Hwang, Dong-Won;Lee, Hong-Sik;Jin, Yun-Sik;Cho, Chu-Hyun;Kim, Jong-Soo;Rim, Geun.Hee;Park, Won-Zoo;Kim, Jin-Sung;Jung, Jae-Won;Chu, Jeung-Ho
    • Proceedings of the KIEE Conference
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    • pp.2086-2088
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    • 2000
  • Key elements of in the development Electro-Thermal-Chemical propulsion (ETC) are high current pulse shaping, switching and storage bank device with high energy density 300kJ pulse power capacitor bank module for ETC application is designed and fabricated. The tested result are described.

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Analysis of a breakdown in 154 kV STATCON Bank condenser cell (154kV SC Bank 콘덴서 절연파괴 대책연구)

  • Ju H.J.;Khak J.S.;Woo J.W.;Kang Y.W.;shim E.B.
    • Proceedings of the KIEE Conference
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    • pp.537-540
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    • 2004
  • 154 kV 변전소에 설치 운전 중인 SC Bank콘덴서 셀의 절연파괴 고장이 빈번하게 발생되어 전력계통의 운용 덴 변전소 운전에 지장을 주는 사례가 많이 발생하였다. 따라서 이의 고장원인 진단을 통하여 대책수립을 하고자 EMTP(Electro-Magnetic Transient Program)를 이용하여 50의 SC Bank의 정상상태시 과전압, 과전류에 의한 소손현상을 검토하고, 계통조건에 따른 공진점변화와 고조파에 따른 이상전압 및 콘덴서 셀 전압의 상승 현상을 검토 분석하고, 현장 실측을 통하여 고조파성분에 따른 과전압 및 과전류를 분석하여 대책을 제시한 사례 연구의 결과이다.

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Bioconversion of Ginsenoside Rb1 to Compound K using Leuconostoc lactis DC201

  • Piao, Jin-Ying;Kim, Yeon-Ju;Quan, Lin-Hu;Yang, Dong-Uk;Min, Jin-Woo;Son, Seon-Heui;Kim, Sang-Mok;Yang, Deok-Chun
    • Korean Journal of Plant Resources
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    • v.24 no.6
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    • pp.712-718
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    • 2011
  • Ginseng (Panax ginseng) is frequently used in Asian countries as a traditional medicine. The major components of ginseng are ginsenosides. Among these, ginsenoside compound K has been reported to prevent the formation of malignancy and metastasis of cancer by blocking the formation of tumor and suppressing the invasion of cancer cells. In this study, ginsenoside $Rb_1$ was converted into compound K, via secreted ${\beta}$-glucosidase enzyme from the Leuconostoc lactis DC201 isolated, which was extracted from Kimchi. The strain DC201 was suspended and cultured in MRS broth at $37^{\circ}C$. Subsequently, the residue from the cultured broth supernatant was precipitated with EtOH and then dissolved in 20 mM sodium phosphate buffer (pH 6.0) to obtain an enzyme liquid. Meanwhile, the crude enzyme solution was mixed with ginsenoside $Rb_1$ at a ratio of 1:4 (v/v).The reaction was carried out at $30^{\circ}C$ and 190 rpm for 72 hours, and then analyzed by TLC and HPLC. The result showed that ginsenoside Rb1 was transformed into compound K after 72 hours post reaction.